Method for tamping an explosive charge



y 3, 1952 c. K. BAIN 2,596,639

METHOD FOR TAMPING AN EXPLOSIVE CHARGE Filed Feb. 21, 1947 ;"fi I A3 7": i F

FIG.

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INVENTOR CHARLES K. BAIN BY WJW ATTO RNEY Patented May 13, 1952 METHDD FOR TAIVIPING AN EXPLOSIVE CHARGE Charles K. Bain, Bonne Torre, I l/10., assignor to St.

Joseph Lead Company, New York, N. Y., a corporation of New York Application February 21, 1947, Serial No. 730,009

2 Claims. IV

This invention relates to apparatus and method for mechanically tamping' powder Or dynamite into a hole that is to be charged.

Under present methods of blasting, holes are drilled in the earth or rock strata where the charge is to be placed and powder or dynamite is hand tamped into the hole so drilled. Since its inception, the art of powder tamping has remained unchanged, and at present, holes are charged by packing the powder in the hole by hand with a wooden stick or rod. Such method of tamping employs a series of hard blows to the 7 powder which are dealt manually by long, forceful strokes of the arm. In tamping dynamite by this method, the hole is charged by tamping one stick of dynamite at a time and before the stick is placed in th hole, its wrapping is split so that the explosive will be loosened from its package to increase the effects of tamping.

This method requires considerable time and a great expenditure of manual labor. Additionally, it is practically impossible, due to the great amount of physical effort involved, to get. the most experienced workman to make a thoroughly packed charge.

Advancement of the art to include mechanical tamping has been retarded primarily because of safety reasons. Thus, it is necessary to tamp the explosive with a non-metallic, non-conducting rod which will not create sparks generated by static electricity or by contact with rock formation. The use of such a rod has heretofore made mechanical tamping difficult because no suitable means has been provided for ap lying mechanical driving power to the rod. In the instant invention all of these problems have been solved.

It may therefor be stated that a general object of the invention is to provide a paratus and a method for mechanically tamping powder or dynamite into a hole that is to be charged, with absolute safety.

It is also an object of the invenion to provide apparatus and a method for tamping powder or dynamite into a hole which will increase the efficiency of the charge and produce more tons of blasted material per pound of explosive.

A further object of th invention is to provide apparatus and a method for tamping an explosive charge into a hole with greater speed and uniformity than can presently be accomplished.

A still further object of the invention is to provide means for, and to teach a method of, tamping an explosive charge in a hole, which eliminates the human factor, is much safer than the prior art methods, and which greatly reduces the 2 amount of physical effort expenced by anoperator to thereby greatly increase his productivity in terms of superior workmanship and an increased number of charged holes.

Other objects and advantages will become apparent as the description proceeds and a .more comprehensive understanding of the invention will be afforded from the following detailed specification when considered in conjunction with the accompanying drawings, in which Fig. 1 is a side view of a tamping stick adapter embodying the instant invention and showing its association with a power hammer and a tamping stick as used in practicing the method taught,

Fig. 2 is a longitudinal sectional view of the tamping stick adapter illustrated in Fig. 1, and

Figs. 3 and 4 are views illustrating the method taught by the instant invention for charging a hole and showing the results obtained as found by experimentation.

As illustrated in Fig. 1, the invention contemplates a tamping stick ada ter .H which is used with a power hammer l2 and a tamping stick, or rod, 13.

The power hammer [2 may take the form of any one of several types but is preferably a small air hammer commonly known as a chipping hammer. All that is required of th hammer is that it be capable of delivering light blows to the stick I3 as compared with the heavy blows employed in hand tamping, and in rapid succession. The ordinary air chipping hammer delivers such light blows in the order of several per second.

The tamping stick l3 may be fashioned from one of several different kinds of non-conducting, non-metallic material but is preferably made of hard wood in identically the same manner as are the tamring sticks now used for hand tamping.

As is illustrated in Fig. 2, the tamping stick adapter I comprises a metallic shaft which is provided with a shank I l insertable in a chuck if; of the air hammer l2, and a bore H5 adaptable to receive an end of the tamping stick I 3. In practice the tamping stick may be fitted tightly into the bore 56 and the stick and adapter carried as a unit or the two may be carried separately, the tamping stick being placed in the bore I 6 after the adapter is placed in the chuck of the air hammer.

In practicing the method taught by the instant invention, a hole ll (Fig. 4) is charged by placing at least three packages of an explosive, such as sticks of dynamite 58 (Fig. 3), in the hole which has been drilled previously in the earth strata to be blasted. Thus far, this differs over the prior art hand method of tamplng in that a plurality of sticks are tamped at one time as against a single stick and further in that it is not required to first split the sides of the wrapper for the explosive. Thereafter the tamping stick I3 is moved against the foremost stick of explosive and a series of rapidly applied light blows are delivered to the stick by the air hammer 12 through the adapter II. This procedure is repeated until the required number of sticks of dynamite have been tamped into the hole, at which time the charge l9 (Fig. 4) will occupy the position shown.

It is to be noted that the explosive material fills the drilled hole completely, leaving no vacant spaces, such as 2| (Fig. 3) surrounding the charge. This result, which is not usually obtained, accounts for a greatly increased efficiency of the charge and is thought to be attributable to the series of light blows delivered to the stick mechanically as against a fewer number of hard blows delivered by hand.

These facts have been determined experimentally by first charging a hole made in a sectional mold by an expert hand tamper and comparing the results obtained with those developed by tamping the same hole with the method taught by the instant invention.

It will be apparent from the foregoing description that the method of mechanically tamping a hole is far superior to that of hand tamping. It has been found in practice that a charge can be tamped by the above described method in 50-75% less time than that required for tamping the same hole with an identical charge by hand. Further, the amount of physical labor required is reduced to a minimum and greater production per man results. Also, it is possible for charging crews to keep up with drilling crews and better over-all operation of the blasting group results. Moreover, since light tamping blows are used the chances for accidental detonation of the charge are reduced to a minimum for increased safety, and, as has been mentioned previously, the charge is more compactly tamped resulting in increased blasting efllciencies.

Although reference has been made to particular structures in describing the invention in its preferred form, it is not intended that these shall act in a limiting sense. Insofar as any changes or modifications to which the invention is susceptible fall within the appended claims they are considered to be covered as if described.

What is claimed is:

l. A method for tamping an explosive in a hole to be charged comprising the steps of placing a package of an explosive in said hole, engaging said explosive with a tamping stick and mechanically delivering to the stick a succession of light blows rapidly in the order of several per second.

2. A method for tamping an explosive in a hole to be charged comprising the steps of placing a package of an explosive in said hole, engaging said explosive continuously'with an end of a tamping stick and mechanically imparting to the stick a succession of light blows in the order of several per second until the explosive has been tamped into the hole.

CHARLES K. BAIN.

REFERENCES CITED I The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 703,288 Millan June 24, 1902 870,511 Hayes et al. Nov. 5, 1907 1,136,987 Wakfer Apr, 2'7, 1915 1,160,507 Gregory Nov. 16, 1915 1,789,816 Hansen Jan. 30, 1931 FOREIGN PATENTS Number Country Date 248,421 Germany June 21, 1912 530,915 Germany Aug. 3, 1931 

